I. Field
The present disclosure relates generally to communication, and more specifically to transmission techniques in a wireless communication system.
II. Background
A multiple-access system can concurrently communicate with multiple terminals on the forward and reverse links. The forward link (or downlink) refers to the communication link from the base stations to the terminals, and the reverse link (or uplink) refers to the communication link from the terminals to the base stations. Multiple terminals may simultaneously transmit data on the reverse link and/or receive data on the forward link. This is often achieved by multiplexing the multiple data transmissions on each link to be orthogonal to one another in time, frequency and/or code domain. For example, data transmissions for different terminals may be orthogonalized by using different orthogonal codes in a code division multiple access (CDMA) system, by transmitting in different time slots in a time division multiple access (TDMA) system, and by transmitting on different frequency subbands in a frequency division multiple access (FDMA) system or an orthogonal frequency division multiple access (OFDMA) system.
The terminals may transmit various types of data such as, e.g., traffic data, signaling, and pilot. Traffic data refers to data sent by an application (e.g., voice or packet data), signaling refers to data sent to support system operation (e.g., control data), and pilot refers to data that is known a priori by both a transmitter and a receiver. The different types of data may have different requirements and may be transmitted in different manners, e.g., at different rates and in different time intervals. Since signaling and pilot represent overhead, it is desirable for the terminals to transmit signaling and pilot as efficiently as possible.
There is therefore a need in the art for efficient transmission techniques in a multiple-access system.